Sudeshna Paul

Variation in Patient-Sharing Networks of Physicians Across the United States

CONTEXT Physicians are embedded in informal networks that result from their sharing of patients, information, and behaviors. OBJECTIVES To identify professional networks among physicians, examine how such networks vary across geographic regions, and determine factors associated with physician connections. DESIGN, SETTING, AND PARTICIPANTS Using methods adopted from social network analysis, Medicare administrative data from 2006 were used to study 4,586,044 Medicare beneficiaries seen by 68,288 physicians practicing in 51 hospital referral regions (HRRs). Distinct networks depicting connections between physicians (defined based on shared patients) were constructed for each of the 51 HRRs. MAIN OUTCOMES MEASURES Variation in network characteristics across HRRs and factors associated with physicians being connected. RESULTS The number of physicians per HRR ranged from 135 in Minot, North Dakota, to 8197 in Boston, Massachusetts. There was substantial variation in network characteristics across HRRs. For example, the mean (SD) adjusted degree (number of other physicians each physician was connected to per 100 Medicare beneficiaries) across all HRRs was 27.3 (range, 11.7-54.4); also, primary care physician relative centrality (how central primary care physicians were in the network relative to other physicians) ranged from 0.19 to 1.06, suggesting that primary care physicians were more than 5 times more central in some markets than in others. Physicians with ties to each other were far more likely to be based at the same hospital (69.2% of unconnected physician pairs vs 96.0% of connected physician pairs; adjusted rate ratio, 0.12 [95% CI, 0.12-0.12]; P < .001), and were in closer geographic proximity (mean office distance of 21.1 km for those with connections vs 38.7 km for those without connections, P < .001). Connected physicians also had more similar patient panels in terms of the race or illness burden than unconnected physicians. For instance, connected physician pairs had an average difference of 8.8 points in the percentage of black patients in their 2 patient panels compared with a difference of 14.0 percentage points for unconnected physician pairs (P < .001). CONCLUSIONS Network characteristics vary across geographic areas. Physicians tend to share patients with other physicians with similar physician-level and patient-panel characteristics.

Using administrative data to identify naturally occurring networks of physicians.

Background:Physicians naturally form networks. Networks could form a rational basis for Accountable Care Organizations (ACOs) for defined populations of Medicare beneficiaries. Objectives:To use methods from network science to identify naturally occurring networks of physicians that might be best suited to becoming ACOs. Research Design, Subjects, and Measures:Using nationally representative claims data from the Medicare program for CY 2006 on 51 hospital referral regions (HRRs), we used a network science–based community-detection algorithm to identify groups of physicians likely to have preestablished relationships. After assigning patients to networks based upon visits with a primary care physician, we examined the proportion of care delivered within communities and compared our results with potential ACOs organized around single hospitals. Results:We studied 4,586,044 Medicare beneficiaries from 51 HRRs who were seen by 68,288 active physicians practicing in those HRRs. The median community-based network ACO had 150 physicians with 5928 ties, whereas the median hospital-based network ACO had 96 physicians with 3276 ties. Among patients assigned to networks via their primary care physicians, seventy-seven percent of physician visits occurred with physicians in the community-based networks as compared with 56% with physicians in the hospital-based networks; however, just 8% of specialist visits were to specialists within the hospital-based networks as compared with 60% of specialist visits within the community-based networks. Some markets seemed better suited to developing ACOs based on network communities than others. Conclusions:We present a novel approach to identifying groups of physicians that might readily function as ACOs. Organic networks identified and defined in this natural and systematic manner already have physicians who exhibit close working relationships, and who, importantly, keep the vast majority of care within the networks.

Variation in Dialysis Facility Referral for Kidney Transplantation Among Patients With End-Stage Renal Disease in Georgia

IMPORTANCE Dialysis facilities in the United States are required to educate patients with end-stage renal disease about all treatment options, including kidney transplantation. Patients receiving dialysis typically require a referral for kidney transplant evaluation at a transplant center from a dialysis facility to start the transplantation process, but the proportion of patients referred for transplantation is unknown. OBJECTIVE To describe variation in dialysis facility-level referral for kidney transplant evaluation and factors associated with referral among patients initiating dialysis in Georgia, the US state with the lowest kidney transplantation rates. DESIGN, SETTING, AND PARTICIPANTS Examination of United States Renal Data System data from a cohort of 15,279 incident, adult (18-69 years) patients with end-stage renal disease from 308 Georgia dialysis facilities from January 2005 to September 2011, followed up through September 2012, linked to kidney transplant referral data collected from adult transplant centers in Georgia in the same period. MAIN OUTCOMES AND MEASURES Referral for kidney transplant evaluation within 1 year of starting dialysis at any of the 3 Georgia transplant centers was the primary outcome; placement on the deceased donor waiting list was also examined. RESULTS The median within-facility percentage of patients referred within 1 year of starting dialysis was 24.4% (interquartile range, 16.7%-33.3%) and varied from 0% to 75.0%. Facilities in the lowest tertile of referral (<19.2%) were more likely to treat patients living in high-poverty neighborhoods (absolute difference, 21.8% [95% CI, 14.1%-29.4%]), had a higher patient to social worker ratio (difference, 22.5 [95% CI, 9.7-35.2]), and were more likely nonprofit (difference, 17.6% [95% CI, 7.7%-27.4%]) compared with facilities in the highest tertile of referral (>31.3%). In multivariable, multilevel analyses, factors associated with lower referral for transplantation, such as older age, white race, and nonprofit facility status, were not always consistent with the factors associated with lower waitlisting. CONCLUSIONS AND RELEVANCE In Georgia overall, a limited proportion of patients treated with dialysis were referred for kidney transplant evaluation between 2005 and 2011, but there was substantial variability in referral among facilities. Variables associated with referral were not always associated with waitlisting, suggesting that different factors may account for disparities in referral.

Bidirectional psychoneuroimmune interactions in the early postpartum period influence risk of postpartum depression

More than 500,000 U.S. women develop postpartum depression (PPD) annually. Although psychosocial risks are known, the underlying biology remains unclear. Dysregulation of the immune inflammatory response and the hypothalamic-pituitary-adrenal (HPA) axis are associated with depression in other populations. While significant research on the contribution of these systems to the development of PPD has been conducted, results have been inconclusive. This is partly because few studies have focused on whether disruption in the bidirectional and dynamic interaction between the inflammatory response and the HPA axis together influence PPD. In this study, we tested the hypothesis that disruption in the inflammatory-HPA axis bidirectional relationship would increase the risk of PPD. Plasma pro- and anti-inflammatory cytokines were measured in women during the 3rd trimester of pregnancy and on Days 7 and 14, and Months 1, 2, 3, and 6 after childbirth. Saliva was collected 5 times the day preceding blood draws for determination of cortisol area under the curve (AUC) and depressive symptoms were measured using the Edinburgh Postpartum Depression Survey (EPDS). Of the 152 women who completed the EPDS, 18% were depressed according to EDPS criteria within the 6months postpartum. Cortisol AUC was higher in symptomatic women on Day 14 (p=.017). To consider the combined effects of cytokines and cortisol on predicting symptoms of PPD, a multiple logistic regression model was developed that included predictors identified in bivariate analyses to have an effect on depressive symptoms. Results indicated that family history of depression, day 14 cortisol AUC, and the day 14 IL8/IL10 ratio were significant predictors of PPD symptoms. One unit increase each in the IL8/IL10 ratio and cortisol AUC resulted in 1.50 (p=0.06) and 2.16 (p=0.02) fold increases respectively in the development of PPD. Overall, this model correctly classified 84.2% of individuals in their respective groups. Findings suggest that variability in the complex interaction between the inflammatory response and the HPA axis influence the risk of PPD.

A Randomized Trial to Reduce Disparities in Referral for Transplant Evaluation

Georgia has the lowest kidney transplant rates in the United States and substantial racial disparities in transplantation. We determined the effectiveness of a multicomponent intervention to increase referral of patients on dialysis for transplant evaluation in the Reducing Disparities in Access to kidNey Transplantation Community Study (RaDIANT), a randomized, dialysis facility-based, controlled trial involving >9000 patients receiving dialysis from 134 dialysis facilities in Georgia. In December of 2013, we selected dialysis facilities with either low transplant referral or racial disparity in referral. The intervention consisted of transplant education and engagement activities targeting dialysis facility leadership, staff, and patients conducted from January to December of 2014. We examined the proportion of patients with prevalent ESRD in each facility referred for transplant within 1 year as the primary outcome, and disparity in the referral of black and white patients as a secondary outcome. Compared with control facilities, intervention facilities referred a higher proportion of patients for transplant at 12 months (adjusted mean difference [aMD], 7.3%; 95% confidence interval [95% CI], 5.5% to 9.2%; odds ratio, 1.75; 95% CI, 1.36 to 2.26). The difference between intervention and control facilities in the proportion of patients referred for transplant was higher among black patients (aMD, 6.4%; 95% CI, 4.3% to 8.6%) than white patients (aMD, 3.7%; 95% CI, 1.6% to 5.9%; P<0.05). In conclusion, this intervention increased referral and improved equity in kidney transplant referral for patients on dialysis in Georgia; long-term follow-up is needed to determine whether these effects led to more transplants.

Perineal Injury During Childbirth Increases Risk of Postpartum Depressive Symptoms and Inflammatory Markers.

INTRODUCTION Perineal lacerations during childbirth affect more than 65% of women in the United States. Little attention has been given to the long-term biologic consequences associated with perineal lacerations or possible associations with postpartum mental health. In this article, we describe the results of a study that explored inflammatory cytokines in women who reported perineal lacerations during childbirth and the relationship with stress and depressive symptoms during the first 6 months postpartum. METHODS A repeated measures design was used to explore the relationship between varying degrees of perineal lacerations, inflammatory cytokines, postpartum stress, and depressive symptoms in 153 women over 6 months. Depressive symptoms were measured using the Edinburgh Postnatal Depression Scale (EPDS), and maternal stress was measured using the Perceived Stress Scale. Plasma was analyzed for proinflammatory (tumor necrosis factor alpha, interleukin 6 (IL-6), interleukin-1 beta, interferon gamma) and anti-inflammatory (interleukin 10) cytokines. Levels of cytokines were compared between women with or without varying degrees of injury. RESULTS A relationship was identified between symptoms of depression and a second-degree or more severe perineal laceration starting at one month postpartum (P = .04) and continuing through 3 months postpartum (P = .03). Similarly, stress symptoms were higher at 3 months postpartum (P = .02). Markers of inflammation were significantly higher among this group, with IL-6 increased at 2 weeks postpartum (P = .02) and remaining elevated through 2 months postpartum (P = .003); there were also significant differences in pro- to anti-inflammatory cytokine ratios out to 6 months postpartum. Regression analysis indicated that second-degree or more severe lacerations accounted for 5.9% of the variance in EPDS score at one month postpartum (P = .024, F = 2.865, t = 2.127), increasing substantially when the one month stress score was included as well. DISCUSSION This study suggests that perineal lacerations, inflammation, stress, and depressed mood are associated; however, more research is needed to elucidate the actual relationship between inflammation and mental health in women who experience such injuries.

Transplant Center Patient Navigator and Access to Transplantation among High-Risk Population A Randomized, Controlled Trial

BACKGROUND AND OBJECTIVES Barriers exist in access to kidney transplantation, where minority and patients with low socioeconomic status are less likely to complete transplant evaluation. The purpose of this study was to examine the effectiveness of a transplant center-based patient navigator in helping patients at high risk of dropping out of the transplant evaluation process access the kidney transplant waiting list. DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS We conducted a randomized, controlled trial of 401 patients (n=196 intervention and n=205 control) referred for kidney transplant evaluation (January 2013 to August 2014; followed through May 2016) at a single center. A trained navigator assisted intervention participants from referral to waitlisting decision to increase waitlisting (primary outcome) and decrease time from referral to waitlisting (secondary outcome). Time-dependent Cox proportional hazards models were used to determine differences in waitlisting between intervention and control patients. RESULTS At study end, waitlisting was not significantly different among intervention (32%) versus control (26%) patients overall (P=0.17), and time from referral to waitlisting was 126 days longer for intervention patients. However, the effectiveness of the navigator varied from early (<500 days from referral) to late (≥500 days) follow-up. Although no difference in waitlisting was observed among intervention (50%) versus control (50%) patients in the early period (hazard ratio, 1.03; 95% confidence interval, 0.69 to 1.53), intervention patients were 3.3 times more likely to be waitlisted after 500 days (75% versus 25%; hazard ratio, 3.31; 95% confidence interval, 1.20 to 9.12). There were no significant differences in intervention versus control patients who started evaluation (85% versus 79%; P=0.11) or completed evaluation (58% versus 51%; P=0.14); however, intervention patients had more living donor inquiries (18% versus 10%; P=0.03). CONCLUSIONS A transplant center-based navigator targeting disadvantaged patients improved waitlisting but not until after 500 days of follow-up. However, the absolute effect was relatively small.

Standardized Transplantation Referral Ratio to Assess Performance of Transplant Referral among Dialysis Facilities

BACKGROUND AND OBJECTIVES For patients with ESRD, referral from a dialysis facility to a transplant center for evaluation is an important step toward kidney transplantation. However, a standardized measure for assessing clinical performance of dialysis facilities transplant access is lacking. We describe methodology for a new dialysis facility measure: the Standardized Transplantation Referral Ratio. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Transplant referral data from 8308 patients with incident ESRD within 249 dialysis facilities in the United States state of Georgia were linked with US Renal Data System data from January of 2008 to December of 2011, with follow-up through December of 2012. Facility-level expected referrals were computed from a two-stage Cox proportional hazards model after patient case mix risk adjustment including demographics and comorbidities. The Standardized Transplantation Referral Ratio (95% confidence interval) was calculated as a ratio of observed to expected referrals. Measure validity and reliability were assessed. RESULTS Over 2008-2011, facility Standardized Transplantation Referral Ratios in Georgia ranged from 0 to 4.87 (mean =1.16, SD=0.76). Most (77%) facilities had observed referrals as expected, whereas 11% and 12% had Standardized Transplantation Referral Ratios significantly greater than and less than expected, respectively. Age, race, sex, and comorbid conditions were significantly associated with the likelihood of referral, and they were included in risk adjustment for Standardized Transplantation Referral Ratio calculations. The Standardized Transplantation Referral Ratios were positively associated with evaluation, waitlisting, and transplantation (r=0.46, 0.35, and 0.20, respectively; P<0.01). On average, approximately 33% of the variability in Standardized Transplantation Referral Ratios was attributed to between-facility variation, and 67% of the variability in Standardized Transplantation Referral Ratios was attributed to within-facility variation. CONCLUSIONS The majority of observed variation in dialysis facility referral performance was due to characteristics within a dialysis facility rather than patient factors included in risk adjustment models. Our study shows a method for computing a facility-level standardized measure for transplant referral on the basis of a pilot sample of Georgia dialysis facilities that could be used to monitor transplant referral performance of dialysis facilities.

Symptom challenges after atrial fibrillation ablation

Background: It is unclear what symptom challenges occur during the recovery phase after atrial fibrillation (AF) ablation. Objectives: This longitudinal pilot study explored the patient perspective of the first six months following an AF ablation. Methods: Telephone interviews and questionnaires were used with 20 patients at baseline, at 1, 3, and 6 months after AF ablation. Telephone interview data were analyzed using content analysis. Longitudinal outcomes were analyzed using repeated measures analysis of variance (ANOVA). Results: Mean age was 65 ± 7 years and the sample was 55% female. The severity and duration of fatigue was the most concerning symptom. Patient expectations differed from providers’ expectations. Recovery was a much slower process than patients expected. Conclusions: Patients struggled to manage symptoms after AF ablation. A more accurate understanding of the symptom challenges following AF ablation could lead to development of more realistic education to improve patient self‐management.

Dietary Behaviors and Glucose Metabolism in Young Adults at Risk for Type 2 Diabetes

Purpose The purpose of the study was to examine the associations between dietary behaviors and glucose metabolism in high-risk young adults to increase the precision of nutrition education to prevent early onset type 2 diabetes (T2D). Method Using a descriptive, cross-sectional study design, 106 overweight or obese sedentary young adults ages 18-29 years from the Atlanta metropolitan area were recruited to screen diabetes risk. Survey questionnaires, anthropometric assessment, blood pressure (BP), and laboratory data were collected in a clinical research unit. The Web-based HOMA2 calculator was used to calculate beta cell function and insulin sensitivity. Results The final sample included 103 participants. There were similar patterns of diet (caloric intake and dietary quality) between African Americans and non-African Americans, whereas African Americans showed hyperinsulinemia compared with non-African Americans. When young adults consumed a good quality diet (appropriate carbohydrate intakes; high fiber, low saturated fat but protein rich diet), their insulin resistance was decreased. There was a marginal interaction effect between insulin sensitivity and beta cell function by race. Systolic BP was higher in African Americans, and total cholesterol, triglycerides, and low-density lipoprotein cholesterol were higher in non-African Americans. Conclusion Findings are useful to develop age-specific nutrition guidelines to prevent early onset T2D in high-risk young adults.